In that type of motor, the distributor and the distribution cover belong to the stator and are generally secured to each other and constrained to rotate one with the other so as to obtain a relative angular position that is very accurate between the distributor and the reaction member which is itself secured to rotate with the distribution cover. To secure the parts in this way and obtain such accurate positioning, various systems have been proposed. Thus, the distributor has been provided with a radial flange extending between the cylinder block and the distribution cover, and an axial peg has been provided to secure the flange to the distribution cover. Other systems using tenons and notches have also been provided.
Although those various solutions do indeed make it possible to ensure positioning in rotation, at least those which use the radial flange suffer from the major drawback of requiring special machining of the distributor and of thereby increasing manufacturing costs. In addition, the presence of the flange increases the axial length of the motor.
Furthermore, it is necessary to take very great care in assembling the motor. In particular the distributor must be accurately positioned in the distribution cover and the regions of the first and second connection faces respectively connected to the feed duct and to the exhaust duct must naturally be completely isolated form each other, which means that sealing gaskets must be provided between the first and second connection faces, and said gaskets must be accurately positioned.
When assembly is complete, it is necessary to make provision for a small amount of axial movement between the distributor and the distribution cover, thus enabling the distribution face to bear against the communication face of the cylinder block.